This invention relates in general to light-producing materials, and in particular to novel self-glowing solid materials and their use in novel tracer ammunition. This invention also relates in particular to novel illuminants and their use in novel illumination devices.
Tracer ammunition includes bullets and other projectiles that include a mechanism to provide a visible artifact enabling the shooter to see the path of the ammunition upon firing. Tracer ammunition may include a small pyrotechnic charge of powder filled into a cavity manufactured into the base. This charge can be ignited by the burning gun powder, and, once ignited, burns very brightly enough to be visible to the bare eye. The tracer allows the shooter to see the projectile trajectory and make aiming corrections as necessary.
Conventional tracer ammunition suffers from the disadvantage of being visible not only to the shooter but also to others, including potentially the target or enemies. This allows the enemy to identify the source of the gunfire and to return fire to the shooter. Conventional tracer ammunition also suffers from the disadvantage that as the powder pyrotechnic charge burns and leaves the cavity, the mass of the projectile decreases, and as a result the ammunition has erratic terminal ballistics which diminish targeting accuracy.
The powdered pyrotechnic materials conventionally used in tracer ammunition create environmental and hazardous material problems. They are dangerous and difficult to transport, handle and machine, which increases costs. The exothermic incendiary nature of the pyrotechnic materials makes them a fire hazard. Thus, for example, tracer ammunition has frequently resulted in fires on training ranges.
The patent literature includes inventions relating to tracer ammunition. For example, U.S. Pat. No. 8,402,896 by Hollerman et al. (University of Louisiana), “Hybrid-Luminescent Munition Projectiles”, involves small arms tracers and their observability. U.S. Pat. No. 7,661,368 by Riess et al. (RUAG Ammotec), “Hard-Core Jacketed Bullet with Tracer Composition . . . ”, discloses tracer bullets containing an illuminant composition. The patents differ from the present invention in the materials used, the mode of action, and other aspects.
There is still a need for an improved tracer ammunition that avoids the performance and safety disadvantages of conventional tracer ammunition, and that is suitable for military and recreational shooting.
Light-producing chemicals (aka, illuminants) are widely used in the pyrotechnics and defense industries to add bright effects to an application or event. For example, military bases often make use of “spotting” rounds when training gun crews. These rounds include a warhead containing an illuminant fill that produces a flash of light upon impact, thereby allowing the crew to track the proximity of its impact about the intended target and make any necessary aiming adjustments.
The ability to detect or “see” where the round is going or where it hits is critical to the training exercise. This requires the use of an illuminant that produces a luminous signature that is visible to the bare eye at downrange distances and that persists for a sufficiently long duration (e.g., ≥1 second). Current illuminants are not always ideal in the visibility or duration of their signature.
Additionally, current illuminants comprise environmentally hazardous chemicals, such as derivatives of chlorine (perchlorates). New environmental regulations are forthcoming which will require the elimination of such toxic and contaminating chemicals from use.
The patent literature includes inventions relating to military training rounds that produce a visible signature to mark their point of impact. For example, US Patent Application No. 2013/0199396 by Kroden et al. (Amtec), “Non-Dud Signature Training Cartridge and Projectile”, discloses a military training cartridge projectile containing a pyrophoric powder that ignites and burns to provide a detectable indication of projectile impact with an object. U.S. Pat. No. 8,783,186 by Scanlon et al. (Alloy Surfaces), “Use of Pyrophoric Payload Material in Ammunition Training Rounds”, discloses ammunition containing a pyrophoric metal powder that produces a bright flash when the ammunition hits a target. The patent documents differ from the present invention in the materials used, the resulting signature, and other aspects.
There is still a need for improved illuminants that are “green” so that they meet environmental regulations, particularly illuminants suitable for use in projectiles, and that maintain or exceed the illuminating properties of the chemicals they are replacing.